GET/POST arguments are available in the arguments property, which
maps arguments names to lists of values (to support multiple values
for individual names). Names are of type str, while arguments
are byte strings. Note that this is different from
RequestHandler.get_argument, which returns argument values as
unicode strings.

An HTTP request is attached to a single HTTP connection, which can
be accessed through the “connection” attribute. Since connections
are typically kept open in HTTP/1.1, multiple requests can be handled
sequentially on a single connection.

By default, the return value is a dictionary (or None, if no
client certificate is present). If binary_form is true, a
DER-encoded form of the certificate is returned instead. See
SSLSocket.getpeercert() in the standard library for more
details.
http://docs.python.org/library/ssl.html#sslsocket-objects

Supports application/x-www-form-urlencoded and
multipart/form-data. The content_type parameter should be
a string and body should be a byte string. The arguments
and files parameters are dictionaries that will be updated
with the parsed contents.